While many computer controlled machines are designed to automatically record data relevant to the performance of the machine, the analysis of this data is generally not automatic. This is especially true for machines which are used to perform a variety of different processes in an industrial environment. As a result, discovery of process control problems tends to be delayed until there is a noticeable degradation in the quality of the product being made or in the process being performed.
The present invention provides a system and method of database management that facilitates the performance of data management and analysis tasks. At the push of just a few buttons, the present invention automatically sorts through the measurement data stored in the system and performs a specified data management task, such as displaying a trend chart for previously recorded data for a specified process, of for displaying on a single computer screen, side by side, the resistivity maps of a dozen wafers so as to allow visual comparison of those maps.
Additional background concerning user interfaces for facilitating the analysis of measurement data can be obtained from the assignee's previously obtained patents, including U.S. Pat. Nos. 4,679,137, 4,805,89, 4,843,538, 4,873,623, and 4,951,190, hereby incorporated by reference.
The invention described in this specification may be applied generally in computer controlled machines which perform various production or testing processes. It may also be applied to data collection and data base management programs. However, the detailed description of the invention will be given in terms of analyzing measurement data from automated resistivity testers, which perform sheet resistance mapping of semiconductor wafers, and automated film thickness testers, which map the thickness of films deposited on semiconductor wafers. Such equipment is used to characterize the performance of semiconductor wafer manufacturing equipment utilized to form surface layers as part of the process of manufacturing semiconductor devices such as, for example, large scale integrated circuits.
The preferred version of an automated resistivity tester which generates appropriate measurement data to be analyzed using this invention is disclosed in U.S. Pat. No. 4,723,207, entitled "APPARATUS AND METHODS FOR SEMICONDUCTOR WAFER TESTING," incorporated herein by reference for background information.
The correctness and uniformity of implant dosage across a semiconductor wafer can be determined in an automatic sheet resistance mapping system which has the capability of taking multiple test readings in both a contour map and diameter scan mode. From these tests and printouts, the engineer in charge of a process can determine whether the ion implantation equipment is operating properly.
To encourage the use of testing equipment such as automated resistivity testers, it is important to provide an overall computer control program for the tester which is easy for the engineer to set up to perform in-process monitoring measurements which will provide meaningful data.